Muffler for an exhaust system

ABSTRACT

The present invention relates to a muffler for an exhaust system of an internal combustion engine having an exhaust gas-carrying first pipe which is connectable to a first exhaust line of the exhaust system or forms an integral component of the first exhaust line, and an exhaust gas-carrying second pipe which is connectable to a second exhaust line of the exhaust system or forms an integral component of the second exhaust line. To design the muffler to be as compact as possible, a housing of the muffler includes a damper space situated between the pipes and has two longitudinal side walls each formed by a wall section of one of the pipes that is permeable for airborne sound.

FIELD OF THE INVENTION

The present invention relates to a muffler for an exhaust system of an internal combustion engine. The invention also relates to an exhaust system equipped with such a muffler.

BACKGROUND OF THE INVENTION

In dual-flow exhaust systems, i.e., in exhaust systems having two exhaust lines with exhaust gas flowing through them in parallel, it is customary for a muffler to be provided at approximately half the distance between the internal combustion engine and the tailpipes opening into the environment, with the two exhaust lines being assigned jointly to the muffler, which is usually referred to as a central muffler. If the exhaust system together with the internal combustion engine is accommodated in a motor vehicle, the two exhaust lines may be installed in a type of tunnel along the undercarriage of the vehicle when the internal combustion engine is mounted in the front end, said tunnel optionally being open at the bottom. The dimensions of this tunnel must be selected so that a critical thermal load on the tunnel walls can be prevented. At the same time, an attempt is made to make the dimensions of the tunnel as small as possible to thereby minimize any negative effects in the interior of the vehicle. Design space problems may occur, for example, if the dual-flow exhaust system must be equipped with a muffler in the area of the tunnel.

A traditional muffler, which is tied jointly into two parallel exhaust lines, usually includes a housing with two side walls opposite one another in the longitudinal direction of the exhaust lines. The two exhaust lines lead into the one side wall and out of the other side wall. A jacket of the housing surrounds in the circumferential direction the two side walls and thus the two exhaust lines inasmuch as they are continued in the interior of the housing. In any case, the cross section of the housing protrudes over the individual cross sections of the exhaust lines with regard to the longitudinal direction of the exhaust lines in each radial direction. To be able to accommodate such a muffler in the tunnel, the tunnel must be enlarged accordingly in the area of the muffler. Such a local increase in the size of the tunnel leads to unwanted negative effect on the interior of the vehicle and is also associated with an increased manufacturing complexity.

SUMMARY OF THE INVENTION

The invention is based on the general idea of integrating two pipes through which exhaust can flow and to which the exhaust lines are connectable or which are formed by longitudinal sections of the exhaust lines into the housing of the muffler in such a way that they form two exterior longitudinal side walls of the housing. In this way, the muffler is bordered by the aforementioned pipes in the area of these longitudinal side walls, so that the housing is at any rate arranged between the two pipes and thus between the two exhaust lines. In a plane containing the two pipes, i.e., the two exhaust lines, the muffler thus needs no more room than the two pipes without the housing and/or the two exhaust lines without the muffler anyway.

To provide the muffler with a damper space, which has a volume equal to the volume of the traditional central muffler, the muffler must be lengthened accordingly in the longitudinal direction of the pipes, i.e., the exhaust lines.

In an embodiment of the invention, the housing may be designed so that it is situated inside an outside contour of at least one of the pipes or protrudes maximally by 20% beyond this outside contour in a viewing direction oriented from one pipe to the other pipe. As a result of this design, the muffler needs only slightly more space or none at all across the longitudinal direction of the pipes, i.e., the exhaust lines and across the aforementioned viewing direction than do the pipes without the housing and/or the exhaust lines without the muffler. For installation of the exhaust system in a vehicle, this means that the tunnel need be enlarged only slightly in this direction or not at all.

It is self-evident that the aforementioned features and those yet to be explained below may be used not only in the particular combination given but also in other combinations or alone without going beyond the scope of the present invention.

Preferred exemplary embodiments of the invention are illustrated in the drawings and are explained in greater detail in the following description, wherein the same reference numerals refer to the same or similar or functionally identical components.

BRIEF DESCRIPTION OF THE DRAWINGS

The figures show schematically:

FIG. 1 shows a simplified schematic diagram of an exhaust system;

FIG. 2 shows a perspective view of an embodiment of the muffler,

FIG. 3 shows a simplified sectional view of the muffler according to sectional lines III in FIG. 1,

FIG. 4 shows a view like that in FIG. 2 but in another embodiment,

FIG. 5 a-5 c show simplified sectional views of the muffler according to sectional lines V in FIG. 1 in different embodiments.

DETAILED DESCRIPTION OF THE INVENTION

According to FIG. 1, an exhaust system 1 includes two exhaust lines 2, 3 with the help of which exhaust gas from an internal combustion engine 4 is emitted into an environment of the internal combustion engine 4 and/or a vehicle equipped therewith. Therefore, exhaust gas formed by the internal combustion engine 4 during operation can flow in parallel through the two exhaust lines 2, 3. According to this invention, a muffler 5 is connected jointly to the two exhaust lines 2, 3 and serves to influence the acoustics of the exhaust system 1. The muffler 5 has two pipes carrying the exhaust, namely a first pipe 6 and a second pipe 7.

FIG. 1 shows an embodiment having an integral design. The muffler 5 is integrated into the exhaust system 1 in such a way that the first pipe 6 is formed by a longitudinal section of the first exhaust line 2, while the second pipe 7 is formed by a longitudinal section of the second exhaust line 3. In contrast with that, FIGS. 2 and 4 show two embodiments in which the pipes 6, 7 form separate components with respect to the exhaust lines 2, 3, to which the exhaust lines 2, 3 can be connected. In the installed state, the first exhaust line 2 is connected to the first pipe 6, while the second exhaust line 3 is connected to the second pipe 7. Although the diagrams in FIGS. 3 and 5 refer to the integral design illustrated in FIG. 1, they are also readily applicable to the embodiments having separate pipes 6, 7, so the reference numerals for the exhaust lines 2, 3 are also to be found there.

The muffler 5 also has a housing 8 which contains a damper space 9. This damper space 9 is arranged between the two pipes 6, 7. The damper space 9 may be filled at least partially with a damper material (not shown here) which has an absorbing effect for airborne sound.

The housing 8 has two longitudinal side walls 10, 11 which extend in the longitudinal direction of the pipes 6, 7, i.e., the exhaust lines 2, 3 prevailing in the area of the muffler 5. These longitudinal side walls 10, 11 of the housing 8 are formed according to this invention by wall sections (not identified separately) of the two pipes 6, 7. Said wall sections form the longitudinal side walls 10, 11, so these wall sections are also referred to below as 10 and/or 11. These wall sections 10, 11 are designed to be permeable for airborne sound, so that the airborne sound conveyed in the exhaust lines 2, 3 may pass through the wall sections 10, 11 into the damper space 9 to be dampened there in a suitable manner, e.g., by means of a damper material. Due to this design, the two pipes 6, 7 form the lateral borders of the housing 8 and/or the muffler 5 in the area of the longitudinal side walls 10, 11.

In the embodiments shown here, the two pipes 6, 7 each have a linear course, at least in a longitudinal section assigned to the housing 8. Such a linear course simplifies the manufacture of the muffler 5. In the embodiments in FIGS. 1 and 2 the pipes 6, 7 are also arranged so that they run parallel to one another at least in the area of the housing 8. This also makes it possible to simplify the assembly of the muffler 5. In contrast with that, in the embodiments shown in FIG. 4, the linear pipes 6, 7 are arranged at an inclination to one another in such a way that their longitudinal directions intersect. Such an embodiment may be advantageous for certain installation situations.

According to FIG. 3, a width 12 of the muffler 5 is determined by the spacing of the two pipes 6, 7 measured on the exterior longitudinal sides facing away from one another. This means that the muffler 5 does not protrude beyond the exterior contour of the pipes 6, 7 in this lateral direction which is in a plane in which the two pipes 6, 7 are situated. Thus in the lateral direction, the muffler 5 requires the same space as the two pipes 6, 7 without the housing 8, i.e., requiring the same space as the two exhaust lines 2, 3 without the muffler 5.

In FIG. 3, a viewing direction 13 is represented by an arrow indicating the view from one pipe, namely the second pipe 7 here, to the other pipe, namely the first pipe 6 here. In this viewing direction 13, the two pipes 6, 7 have an outer contour 14 which is indicated by dash-dot lines. In the present preferred exemplary embodiment, the two pipes 6, 7 are designed with the same cross sections, although that need not be obligatory.

According to the preferred embodiment illustrated in FIG. 3, the housing 8 is inside the outside contour 14 of the pipes 6, 7 in said viewing direction 13. In the present case, an outer distance 15 between the top side 16 and the bottom side 17 of the housing 8 is approximately the same as the outside diameter 18 of the first pipe 6 and/or the second pipe 7. In this design, the muffler 5 thus takes up the same amount of space as the two pipes 6, 7 without the housing 8, i.e., like the two exhaust lines 2, 3 without the muffler 5.

In other embodiments, the housing 8 may also protrude beyond the outside contour 14 in said viewing direction 13, by a maximum of 20% in particular. This yields only a slight increase in space required in the height direction of the muffler 5 in comparison with an embodiment of the exhaust system 1 without the muffler 5.

FIG. 3 also shows an exemplary embodiment with the exhaust line separated by the muffler 5. Therefore, the housing 8 includes a partition 19, which need not necessarily be arranged centrally in the damper space 9. The partition 19 subdivides the damper space 9 into two partial spaces 20, 21 that are separated from one another in an airtight manner. The one partial space 20 communicates with the first pipe 6 while the other partial space 21 communicates with the second pipe 7.

As already mentioned above, the wall sections 10, 11 of the pipes 6, 7 which form the longitudinal side walls 10, 11 of the housing 8 are designed to be permeable for airborne sound. This airborne sound permeability is achieved, for example, by the fact that the respective wall section 10 and/or 11 is perforated according to FIG. 5 a, i.e., is provided with a perforation 22. According to FIG. 5 b, the airborne sound permeability of the wall section 10, 11 may also be implemented by a single window-like opening 23 or by multiple openings 24 as in the embodiment according to FIG. 5 c.

According to FIGS. 5 a through 5 c, the housing 8 may have a housing body 25 having two side walls 26, 27, a top wall 28 and a bottom wall 29. The terms “top” and “bottom” refer to the diagrams and may also refer in particular to the installation situation. The side walls 26, 27, the top wall 28 and the bottom wall 29 are each mounted on two pipes 6, 7. This mounting is preferably accomplished with the help of a weld 30, which is indicated by a thicker line in FIGS. 2 and 4. The respective weld 30 is preferably designed so that it completely surrounds the respective wall section 10, 11. This also seals the housing 8 with respect to the outside at the same time.

According to the embodiment illustrated in FIG. 5 c, the housing body 25 may be assembled from four individual parts, namely one component for each of the side walls 26, 27, the top wall 28 and the bottom wall 29. The individual components 26 through 29 are joined together in an airtight manner via suitable welds 31. It is preferable, however, to have an embodiment like that illustrated in FIGS. 5 a and 5 b, in which the housing body 25 is assembled from two half-shells 32 and 33. The first half-shell 32 according to FIG. 5 a has a top wall 28 and one side wall 26. The second half-shell 33 has a bottom wall 29 and the other side wall 27. In the assembled state, the two half-shells 32, 33 are also joined together in an airtight manner with welds 31.

In the embodiment illustrated in FIG. 5 b, the first half-shell 32 comprises a partial area of each of the two side walls 26, 27 in addition to the top wall 28. Similarly, the second half-shell 33 is designed to be complementary, so that it has the remaining partial areas of the two side walls 26, 27 in addition to the bottom wall 29. Here again, the two half-shells 32, 33 are joined together in an airtight manner by means of welds 31 in the assembled state.

In the embodiments according to FIGS. 5 a and 5 b, the half-shells 32, 33 are preferably manufactured by reshaping, in particular by deep drawing. An embodiment in which the two half-shells 32, 33 are designed as identical parts is especially advantageous because it reduces the manufacturing cost of the muffler 5. 

1. A muffler for an exhaust system of an internal combustion engine comprising: a first exhaust gas-carrying pipe, which is connectable to a first exhaust line of the exhaust system or forms an integral component of the first exhaust line; a second exhaust gas-carrying pipe, which is connectable to a second exhaust line of the exhaust system or forms an integral component of the second exhaust line; and a housing which contains a damper space arranged between said first and second exhaust gas-carrying pipes and has first and second longitudinal side walls, each of said first and second longitudinal side walls formed by a first and a second wall section of each of said first and second exhaust gas-carrying pipes, wherein said first and second wall sections are permeable for airborne sound.
 2. The muffler according to claim 1, wherein said housing is situated within an outer contour of at least one of said first and second exhaust gas-carrying pipes in a viewing direction oriented from said first pipe to said second pipe.
 3. The muffler according to claim 1, wherein said housing protrudes by a maximum of 20% beyond an outer contour of at least one of said first and second exhaust gas-carrying pipes in a viewing direction oriented from said first pipe to said second pipe.
 4. The muffler according to claim 1, wherein at least one of said first and second wall sections forming said first and second longitudinal side walls of said housing is perforated.
 5. The muffler according to claim 1, wherein at least one of said first and second wall sections forming said first and second longitudinal side walls has at least one opening.
 6. The muffler according to claim 1, wherein said housing further comprises a partition which subdivides said damper space into first and second partial spaces separated from one another in an airtight manner, said first partial space communicating with said first exhaust gas-carrying pipe and said second partial space communicating with said second exhaust gas-carrying pipe.
 7. The muffler according to claim 1, wherein at least one of said first and second exhaust gas-carrying pipes has a linear course in a longitudinal section assigned to said housing.
 8. The muffler according to claim 1, wherein said first and second exhaust gas-carrying pipes run parallel to one another at least in the area of said housing.
 9. The muffler according to claim 1, wherein said housing comprises a housing body comprising first and second side walls, a top wall and a bottom wall, each mounted on said first and second exhaust gas-carrying pipes.
 10. The muffler according to claim 9, wherein said housing body comprises first and second half-shells, said first half-shell comprising said top wall and said first side wall or has part of both first and second side walls and said second half-shell comprising said bottom wall and second side wall or the remainder of said first and second side walls.
 11. The muffler according to claim 10, wherein said first and second half-shells are identical.
 12. The muffler according to claim 1, wherein at least one of said first and second exhaust gas-carrying pipes is attached to said housing by means of a weld completely surrounding said first wall section forming said first longitudinal side wall of said housing.
 13. An exhaust system for an internal combustion engine of a motor vehicle, said exhaust system comprising: first and second exhaust lines in parallel through which the exhaust gas can flow; and a muffler connected to said first and second exhaust lines, said muffler comprising: a first exhaust gas-carrying pipe, which is connectable to said first exhaust line of the exhaust system or forms an integral component of said first exhaust line; a second exhaust gas-carrying pipe, which is connectable to said second exhaust line of the exhaust system or forms an integral component of said second exhaust line; and a housing which contains a damper space arranged between said first and second exhaust gas-carrying pipes and has first and second longitudinal side walls, each formed by a first and a second wall section of one of said first and second exhaust gas-carrying pipes that is permeable for airborne sound.
 14. The exhaust muffler system according to claim 13, wherein said housing is situated within an outer contour of at least one of the pipes in a viewing direction oriented from one pipe to the other pipe.
 15. The exhaust muffler system according to claim 13, wherein said housing protrudes by a maximum of 20% beyond an outer contour of at least one of the pipes in a viewing direction oriented from one pipe to the other pipe.
 16. The exhaust muffler system according to claim 13, wherein at least one of said first and second wall sections of said first and second exhaust gas-carrying pipes forming said first and second longitudinal side walls of said housing is perforated.
 17. The exhaust muffler system according to claim 13, wherein at least one of said first and second wall sections of said first and second exhaust gas-carrying pipes forming said first and second longitudinal side walls of said housing has at least one opening.
 18. The exhaust muffler system according to claim 13, wherein said housing comprises a partition which subdivides said damper space into first and second partial spaces separated from one another in an airtight manner, said first partial space communicating with said first exhaust gas-carrying pipe and said second partial space communicating with said second exhaust gas-carrying pipe.
 19. The exhaust muffler system according to claim 13, wherein at least one of said first and second exhaust gas-carrying pipes has a linear course in a longitudinal section assigned to said housing.
 20. The exhaust muffler system according to claim 13, wherein said first and second exhaust gas-carrying pipes run parallel to one another at least in the area of said housing.
 21. The exhaust muffler system according to claim 13, wherein said housing comprises a housing body, said housing body comprising first and second side walls, a top wall and a bottom wall, each mounted on said first and second exhaust gas-carrying pipes.
 22. The exhaust muffler system according to claim 21, wherein said housing body comprises first and second half-shells, said first half-shell comprising said top wall and said first side wall or comprises part of first and second side walls and said second half-shell comprises said bottom wall and said second side wall or the remainder of said first and second side walls.
 23. The exhaust muffler system according to claim 22, wherein said first and second half-shells are identical.
 24. The exhaust muffler system according to claim 13, wherein at least one of said first and second exhaust gas-carrying pipes is attached to said housing by means of a weld completely surrounding said first wall section forming said first longitudinal side wall. 